Process of making c-c-dialkylbarbituric acids.



UNITED STATES Patented May 16, 1905.

PATENT OFFICE.

ERNST PREISWERK, OF BASEL, SWITZERLAND, ASSIGNOR TO THE FIRM OF SOCIETY OF CHEMICAL INDUSTRY IN BASLE, OF BASEL,

, SWITZERLAND.

PROCESS OF MAKING C-C-DIALKYLBARBITURIC ACIDS.

SPECIFICATION forming part of Letters Patent No. 790,263, dated May 16, 1905.

Q Application filed February 21, 1905. Serial No. 2443,765-

To all whom it may concern:

Be'it known that I, ERNST Pnnrswnmgchemist, a citizen of the Swiss Republic, and a resident of Basel, Switzerland, have invented a new and useful Process for the Manufacture of C-C-Dialkylbarbituric Acids, of which the following is a full, clear, and exact specification.

By this invention O-C-dialkylbarbituric acids are made by the action of alkyl esters of carbonic acid on O-O-dialkylmalonamiols in presence of alcoholic sodium ethylate. For instance, with carbonic-acid ethyl ester the reaction takes place according to the following equation:

o 00: Alkyl CONH2 O2H5O Alkyl OO-NH Alkyl CO+2O2H5OH CO-NH.

For instance, sodium may be dissolved in absolute alcohol and the product obtained added to a mixture of the ester of carbonic acid and (J-C-dialkylmalonamid. The mixture may be stirred for some hours in a closed vessel at a suitable temperature. The reaction product dred and fifty-eight parts of finely-powdered (J-O-diethylmalonamid, (E. Fischer, Bar io/rte afar Deutsclwn C/mm'sc/wn GeseZZsc/mft, Vol. 35, page 834:.) The mixture is stirred for some hours in a closed vessel at 100 centigrade. After cooling the product which has separated is filtered oif and again dissolved in water. The solution is separated from unattacked diethylmalonamid by filtration and the diethylbarbituric acid is precipitated from the filtrate by adding hydrochloric acid.

By recrystallization from hot water the O- O-diethylbarbituric acid is obtained in pretty fiat needles, melting at 191 centigrade and diflicultly soluble in cold water.

In analogous manner the other dialkylbarbituric acids may be obtained by substituting in the foregoing example for the diethylmalonamid the other alkyl derivatives of the malonamid.

What I claim is- The described process for the manufacture of O-C-dialkylbarbituric acids by condensing the alkyl esters of carbonic acid with dialkylmalonamids by means of sodium ethylate.

In witness whereof I have hereunto signed my name, this 10th day of February, 1905, in the presence of two subscribing witnesses.

ERNST PREISWERK.

Witnesses:

GEO. GIFFORD, AMAND BRAUN. 

